* HR ↓ (Vital ↓)
  * Coaulopathy (PLT dysfunction)
  * Mydriasis (Catecholamine ↑)

===== Systemic hypothermia : 36℃ 미만 =====

  * Core temperature측정 부위
    * esophagus, nasopharynx, tympanic membrane, pulmonary artery.
  * 32-20℃ : 10℃ 하강에 metabolic oxygen demand 50% 감소. 1℃ 감소에 7%씩 감소.
  * 15-18℃ : Total circulatory arrest.(up to 60min)

===== Hypothermia부작용 =====

  * Reversible coagulopathy : PLT dysfunction, Thrombocytopenia.
  * Cardiac dysfunction : Bradycardia.
  * Left Hb-O2 saturation shift.
  * 말초혈관 저항 증가
  * 술 후 protein catabolism & stress response(→mydriasis)
  * Renal function 감소. 약물 대사 감소.
  * Poor wound healing.

  * Phase Ⅰ : vasodilation, 1-2℃감소/ 1st hour
  * Phase Ⅱ : 3-4 hour
  * Phase Ⅲ : equilibrium, hypothalamus 억제

  * Arrest 가능 : 성인 32-30℃, 소아 28-27℃